Project description:Metabolic reprogramming is a hallmark of human cancer, and cancer-specific metabolism provides opportunities for cancer diagnosis, prognosis, and treatment. However, the underlying mechanisms by which metabolic pathways affect the initiation and progression of colorectal cancer (CRC) remain largely unknown. Here, we demonstrate that cysteine is highly enriched in colorectal tumors compared to adjacent non-tumor tissues, thereby promoting tumorigenesis of CRC. Synchronously importing both cysteine and cystine in colorectal cancer cells is necessary to maintain intracellular cysteine levels. Hypoxia-induced reactive oxygen species (ROS) and ER stress regulate the co-upregulation of genes encoding cystine transporters (SLC7A11, SLC3A2) and genes encoding cysteine transporters (SLC1A4, SLC1A5) through the transcription factor ATF4. Furthermore, the metabolic flux from cysteine to reduced glutathione (GSH), which is critical to support CRC growth, is increased due to overexpression of glutathione synthetase GSS in CRC. Depletion of cystine/cysteine by recombinant cyst(e)inase effectively inhibits the growth of colorectal tumors by inducing autophagy in colorectal cancer cells through mTOR-ULK signaling axis. This study demonstrates the underlying mechanisms of cysteine metabolism in tumorigenesis of CRC, and evaluates the potential of cysteine metabolism as a biomarker or a therapeutic target for CRC.
Project description:Metabolic reprogramming is a hallmark of human cancer and cancer-specific metabolism provide opportunities for cancer diagnosis, prognosis, and treatment. However, how metabolic pathways affect the initiation and progression of colorectal cancer remain largely unknown. Here, we showed cysteine is highly enriched in colorectal tumors compared with adjacent non-tumor tissues to promote tumorigenesis of CRC. Both cystine and cysteine imports are essential to maintain intracellular cysteine level and promote tumor growth and survival. Transporter genes of cystine and cysteine are all upregulated in colorectal cancer by tumor microenvironment induced ROS through transcription factor ATF4. Glutathione synthetase GSS is upregulated and increases cysteine to reduced glutathione flux to support tumor growth and survival in colorectal cancer. Depletion of cystine and cysteine by a recombinant cyst(e)inase effectively reduced the growth of colorectal tumors. Moreover, scavenging cystine and cysteine induces autophagy of colorectal cancer cells through mTOR-ULK signaling axis. With this study, we demonstrate that cysteine metabolism is a key signature of CRC metabolic reprogramming and targeting cysteine metabolism might be an effective approach to treat colon cancer.
Project description:Metastatic cancer causes 90% of cancer deaths. Unlike many primary tumors, metastatic tumors cannot be cured by surgery alone. Metastatic cancer requires chemotherapy. However, metastatic cells are not easily killed by chemotherapy. These problems with chemotherapy are caused in part by the metastatic cell niche: hypoxia. Here we show that the molecule, methyl sulfone, normalized metastatic metabolism of hypoxic breast cancer and melanoma cells by altering several metabolic functions of the cells. Under hypoxia, methyl sulfone decreased expression of the master regulator of hypoxia, HIF-1α, and reduced levels of the glycolytic enzymes, PKM2, LDHA, GLUT1, the pro-angiogenic protein, VEGF, and the iron-sulfur metabolism molecules, miR-210 and transferrin, all of which promote metastasis. Conversely, methyl sulfone increased levels of ISCU1/2 and ferroportin, proteins associated with iron-sulfur cluster biogenesis and iron homeostasis in normal cells. These data identify methyl sulfone as a multi-targeting molecule that blocks the survival/proliferative effect of hypoxia on metastatic cells and brings normality back to cellular metabolism.
Project description:BackgroundLung cancer is the most common adult malignancy accounting for the largest proportion of cancer related deaths. Iron (Fe) is an essential trace element and is a component of several major metabolic pathways playing an important role in many physiological processes. In this study we evaluated the association between Fe concentration in serum, iron metabolism parameters and genetic variaton in 7 genes involved in iron metabolism and anti-oxidative processes with the incidence of lung cancer in Poland.Materials and methodsThe study included 200 lung cancer patients and 200 matched healthy control subjects. We analyzed serum iron concentration and iron metabolism parameters (TIBC, UIBC, serum ferritin and transferrin saturation), and genotyped seven variants in seven genes: HFE, TFR1, HAMP, TF, SOD2, CAT and GPX1.ResultsLung cancer patients compared to their matched controls had significantly higher mean serum iron level (p = 0.01), ferritin level (p = 0.007) and TIBC (p = 0.006). Analysis revealed that higher concentration of iron and ferritin (IVth quartile) compared to the lower concentration (Ist quartile) was associated with over 2-fold increased lung cancer incidence. We also found that higher transferrin saturation (p = 0.01) and lower TIBC (p<0.01) are associated with better survival of lung cancer patients. The analysis of polymorphisms in iron related genes did not reveal a significant difference between lung cancer patients and controls. However, rs10421768 in HAMP showed a borderline statistically significant correlation with lung cancer risk (OR = 2.83, p = 0.05).ConclusionsThe results of this case control study indicate that higher body iron represented by higher Fe and ferritin levels may be associated with lung cancer incidence. Rs10421768 in HAMP may be associated with about 3-times higher lung cancer risk. Higher Fe body content may be associated with better survival of lung cancer patients.
Project description:Tumor hypoxia is a known adverse prognostic factor, and the hypoxic dermal microenvironment participates in melanomagenesis. High levels of hypoxia inducible factor (HIF) expression in melanoma cells, particularly HIF-2α, is associated with poor prognosis. The mechanism underlying the effect of hypoxia on melanoma progression, however, is not fully understood. We report evidence that the effects of hypoxia on melanoma cells are mediated through activation of Snail1. Hypoxia increased melanoma cell migration and drug resistance, and these changes were accompanied by increased Snail1 and decreased E-cadherin expression. Snail1 expression was regulated by HIF-2α in melanoma. Snail1 overexpression led to more aggressive tumor phenotypes and features associated with stem-like melanoma cells in vitro and increased metastatic capacity in vivo. In addition, we found that knockdown of endogenous Snail1 reduced melanoma proliferation and migratory capacity. Snail1 knockdown also prevented melanoma metastasis in vivo. In summary, hypoxia up-regulates Snail1 expression and leads to increased metastatic capacity and drug resistance in melanoma cells. Our findings support that the effects of hypoxia on melanoma are mediated through Snail1 gene activation and suggest that Snail1 is a potential therapeutic target for the treatment of melanoma.
Project description:Metabolic reprogramming is a hallmark of human cancer and cancer-specific metabolism provide opportunities for cancer diagnosis, prognosis, and treatment. However, how metabolic pathways affect the initiation and progression of colorectal cancer remain largely unknown. Here, we showed cysteine is highly enriched in colorectal tumors compared with adjacent non-tumor tissues to promote tumorigenesis of CRC. Both cystine and cysteine imports are essential to maintain intracellular cysteine level and promote tumor growth and survival. Transporter genes of cystine and cysteine are all upregulated in colorectal cancer by tumor microenvironment induced ROS through transcription factor ATF4. Glutathione synthetase GSS is upregulated and increases cysteine to reduced glutathione flux to support tumor growth and survival in colorectal cancer. Depletion of cystine and cysteine by a recombinant cyst(e)inase effectively reduced the growth of colorectal tumors. Moreover, scavenging cystine and cysteine induces autophagy of colorectal cancer cells through mTOR-ULK signaling axis. With this study, we demonstrate that cysteine metabolism is a key signature of CRC metabolic reprogramming and targeting cysteine metabolism might be an effective approach to treat colon cancer.
Project description:An effective therapy for advanced melanoma, a skin cancer with the highest mortality, has not yet been developed. The endocannabinoid system is considered to be an attractive target for cancer treatment. The use of endocannabinoids, such as anandamide (AEA), is considered to be much greater than as a palliative agent. Thus, we checked its influence on various signaling pathways in melanoma cells. Our investigation was performed on four commercial cell lines derived from different progression stages (radial WM35 and vertical WM115 growth phases, lymph node WM266-4 metastasis, solid tumor A375-P metastasis). Cell viability, glucose uptake, quantification of reactive oxygen species production, expression of selected genes encoding glycosyltransferases, quantification of glycoproteins production and changes in the glycosylation profile and migration, as well as in cell elastic properties were analyzed. The cell glycosylation profile was investigated using the biophysical profiling method-the quartz crystal microbalance with dissipation monitoring (QCM-D). Anandamide treatment of only metastatic cells resulted in: an increase in the cell metabolism, a decrease in GFAT-1 and DPM1 expression, followed by a decrease in L1-CAM glycoprotein production, which further influenced the reduction in the cell glycosylation profile and migration. Considering our results, AEA usage is highly recommended in the combined therapy of advanced melanoma.
Project description:Hypoxia occurs in 80% of non-small cell lung carcinoma (NSCLC) cases, leading to treatment resistance. Hypoxia's effects on NSCLC energetics are not well-characterized. We evaluated changes in glucose uptake and lactate production in two NSCLC cell lines under hypoxia in conjunction with growth rate and cell cycle phase distribution. The cell lines A549 (p53 wt) and H358 (p53 null) were incubated under hypoxia (0.1% and 1% O2) or normoxia (20% O2). Glucose and lactate concentrations in supernatants were measured using luminescence assays. Growth kinetics were followed over seven days. Cell nuclei were stained with DAPI and nuclear DNA content was determined by flow cytometry to determine cell cycle phase. Gene expression under hypoxia was determined by RNA sequencing. Glucose uptake and lactate production under hypoxia were greater than under normoxia. They were also significantly greater in A549 compared to H358 cells. Faster energy metabolism in A549 cells was associated with a higher growth rate in comparison to H358 cells under both normoxia and hypoxia. In both cell lines, hypoxia significantly slowed down the growth rate compared to proliferation under normoxic conditions. Hypoxia led to redistribution of cells in the different cycle phases: cells in G1 increased and the G2 population decreased. Glucose uptake and lactate production increase under hypoxia in NSCLC cells indicated greater shunting of glucose into glycolysis rather than into oxidative phosphorylation compared to normoxia, making adenosine triphosphate (ATP) production less efficient. This may explain the redistribution of hypoxic cells in the G1 cell cycle phase and the time increase for cell doubling. Energy metabolism changes were more prominent in faster-growing A549 cells compared to slower-growing H358 cells, indicating possible roles for the p53 status and inherent growth rate of different cancer cells. In both cell lines, genes associated with cell motility, locomotion and migration were upregulated under chronic hypoxia, indicating a strong stimulus to escape hypoxic conditions.
Project description:Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular disease. While intermittent hypoxia (IH) and catecholamine release play an important role in this increased risk, the mechanisms are incompletely understood. We have recently reported that IH causes endothelial cell (EC) activation, an early phenomenon in the development of cardiovascular disease, via IH-induced catecholamine release. Here, we investigated the effects of IH and epinephrine on gene expression in human aortic ECs using RNA-sequencing. We found a significant overlap between IH and epinephrine-induced differentially expressed genes (DEGs) including enrichment in leukocyte migration, cytokine-cytokine receptor interaction, cell adhesion and angiogenesis. Epinephrine caused higher number of DEGs compared to IH. Interestingly, IH when combined with epinephrine had an inhibitory effect on epinephrine-induced gene expression. Combination of IH and epinephrine induced MT1G (Metallothionein 1G), which has been shown to be highly expressed in ECs from parts of aorta (i.e., aortic arch) where atherosclerosis is more likely to occur. In conclusion, epinephrine has a greater effect than IH on EC gene expression in terms of number of genes and their expression level. IH inhibited the epinephrine-induced transcriptional response. Further investigation of the interaction between IH and epinephrine is needed to better understand how OSA causes cardiovascular disease.